Thread: Simple square-route function if you don't want to use cmath

Code:

double My_sqrt(int ToSqrt){
/*If you want, make the prompt here.


*/
double answer=.0000001;
while(answer*answer<ToSqrt){
answer+=.0000001;}
return answer;}

It relies on loops.You can understand it(duh!).I it doesn't work, I just made it up on a dime.
Later.

Took about 4 seconds to find the square root of 64...
I think I'll rely on sqrt() which found it in nanoseconds...

-_-

Oh, the bad thing is it is slow. I can do some operations faster than it.

Things like that aren't meant to be questioned

Use the function pow()...
it will do the job!

"I can do some operations faster than it."

Sorry I don't get what you mean? [/B]

I meant before it finishes, I'm done.

Code:

#include <iostream>

int main( void ){

	float	x = 64;
	
	__asm{					
		FLD x			
		FSQRT			
		FST x			
	}

	std::cout << x << std::endl;

	return 0;
}

Originally posted by Munkey01
Why use ASM for this? Faster?

Maybe....I was just "adding to the mix"

Originally posted by fuh

Code:

double My_sqrt(int ToSqrt){
/*If you want, make the prompt here.


*/
double answer=.0000001;
while(answer*answer<ToSqrt){
answer+=.0000001;}
return answer;}

It relies on loops.You can understand it(duh!).I it doesn't work, I just made it up on a dime.
Later.

ugggggggg. very slow, very useless, arbitrairly bad precision.

Code:

__inline float RSqrt( float number ) {
    long i;
    float x2, y;
    const float threehalfs = 1.5f;
    x2 = number * 0.5f;
    y  = number;
    i  = * (long *) &y;
    i  = 0x5f3759df - (i >> 1);
    y  = * (float *) &i;
    y  = y * (threehalfs - (x2 * y * y));
    return y;
}

In all seriousness, I think i'm going to cry.

If ANYONE can explain to me how that works, i'll make a shrine in your honour and pray at it every day.